1) Field of the Invention
The present invention relates to non-destructive inspection and, more particularly, to non-destructive inspection of a workpiece for defects using an inspection system in conjunction with a coordinate measurement machine and data acquisition system, as well as an associated method.
2) Description of Related Art
Non-destructive testing of structures involves thoroughly examining a structure without harming, or requiring significant disassembly of, the structure. Non-destructive testing is advantageous for many applications in which a thorough inspection of the exterior and/or interior of a structure is required. For example, non-destructive testing is commonly utilized in the aircraft industry to inspect aircraft structures for any type of internal or external damage to the structure. Metallic aircraft structures are typically inspected for corrosion and/or cracking, particularly near fasteners in the structure. Composite structures are typically inspected for any type of damage, such as delamination, occurring anywhere on or within the composite material.
Various types of sensors may be utilized to perform non-destructive testing. One or more sensors may move over the portion of the structure to be examined, and receive data regarding the structure. For example, ultrasonic testing could be used to generate a sound wave through a sensor or probe that is directed towards a part. When there is a flaw in the part, part of the sound wave will reflect back from the flaw and will be detected. A pulse-echo sensor may be utilized to obtain ultrasonic data, such as thickness gauging, detection of laminar defects and porosity, and/or crack detection in the structure. Resonance, pitch/catch or mechanical impedance sensors may be utilized to provide indications of voids or porosity, such as in adhesive bondlines of the structure. In addition, single and dual current eddy current probes, utilizing electromagnetic induction, impart and detect eddy currents within a structure so as to identify cracks and/or corrosion, particularly in metallic or other conductive structures. The data acquired by the sensors is typically processed by a processing element, and the processed data may be presented to a user via a display.
Current portable inspection systems may be automatic or manual. For example, automatic scanners such as the Mobile Automated Scanner (MAUS®) system, developed by The Boeing Company, are proficient in inspecting relatively flat parts such as wing and fuselage skins. One type of MAUS® system automatically moves along the structure via strategically controlled suction cups, while another type includes handheld sensors and an associated carriage that is moved along the structure via manual motion. As such, the MAUS® system not only scans the part, but also processes the data regarding the structure, and associates the data with the exact location on the part from where the data was obtained. The data is used to create C-scans and B-scans so that flaws or other items of interest may be detected on the surface of the part.
Manual inspection systems such as the USN60 (GE Inspection Technologies) and the Epoch III (Panametrics, Inc.) are typically used for portable inspection of in-service and as-manufactured parts, but are only capable of producing an A-scan output inspection. A-scans are less desired as customers become concerned about the probability of detecting a defect when employing the manual inspection of fracture and durability (F/D) parts, which puts the part in jeopardy of being not approved for use. Thus, current manual inspection systems are incapable of producing a more accurate C-scan or B-scan for small to midsize complex shaped parts.
Furthermore, a Coordinate Measurement Machine (CMM) such as that disclosed in U.S. Pat. No. 6,366,831 to Raab includes a portable CMM that implements an articulating arm and software interface. The arm is multijointed and includes a transducer that may be manually positioned for measuring a part. A controller is used as an interface between the transducer and a computer. In use, an experienced human operator directs the transducer along a desired tool path or the path to be traversed during a manufacturing operation on an existing part to produce data that is transferred to a computer numerically controlled (CNC) device. The CNC device uses the data to reproduce the profile of the part emulated by the CMM on a workpiece.
It would therefore be advantageous to provide an inspection system that is capable of producing C-scans and B-scans. Finally, it would be advantageous to provide an inspection system that is portable and capable of inspecting workpieces having complex shapes.